Wheel bearing unit

ABSTRACT

A wheel bearing unit having a wheel hub which is mounted rotatably on a bearing journal by means of two tapered roller bearings which are spaced apart axially. The wheel bearing includes one outer ring, one inner ring and one roller crown ring which is formed from tapered rollers and a bearing cage. The tapered roller bearings are received by their outer rings on one axial stop of the wheel hub such that they are directed counter to one another, and the inner rings of the tapered roller bearings are spaced apart axially from one another by means of a sleeve wherein the wheel hub, tapered roller bearing and sleeve form a self-retaining assembly in the non-installed state of the wheel bearing unit. Both tapered roller bearings are secured axially by one securing means which is received directly on the wheel hub and covers the roller crown ring radially.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is the U.S. national stage application pursuant to 35 U.S.C. §371 of International Patent Application No. PCT/EP2011/061204, filed Jul. 4, 2011, which claims priority from German Patent Application No. 10 2010 047 932.2, filed Oct. 8, 2010, which applications are incorporated herein by reference in their entireties.

FIELD OF THE INVENTION

The invention relates to a wheel bearing unit, in particular for commercial vehicles, having a wheel hub which is mounted rotatably on a bearing journal by means of two tapered roller bearings which are spaced apart from one another axially with in each case one outer ring, one inner ring and one roller crown ring which is arranged between the former and is formed from tapered rollers and a bearing cage for them, the tapered roller bearings being received by means of their outer rings on in each case one axial stop of the wheel hub such that they are directed counter to one another, and the inner rings of the tapered roller bearings being spaced apart axially from one another by means of a sleeve.

BACKGROUND OF THE INVENTION

A wheel bearing unit of the generic type for use in a commercial vehicle is known, for example, from U.S. Pat. No. 6,149,244. Here, a wheel hub which carries a wheel is received rotatably on a bearing journal. Two tapered roller bearings which are received on the wheel hub such that they are spaced apart from one another axially serve for this purpose. Here, the axes of inclination of the tapered rollers are inclined with respect to one another and the outer rings are positioned axially with respect to one another, on corresponding axial stops with respect to one another. In the installed state of the wheel bearing unit, the axial end sides of the inner rings, which end sides point away from one another, are fixed in each case axially on the bearing journal or axially on the lock nut which is screwed onto said bearing journal. The end faces which face one another are positioned axially by means of a sleeve which is arranged between them.

In the non-installed state, the inner rings and the roller crown rings are captively secured and positionally fixed to a limited extent. In particular, as a result of a partly great axial play, the sleeve is not held between the inner rings and can therefore be displaced radially and therefore make mounting of the wheel bearing unit on the bearing journal more difficult.

BRIEF SUMMARY OF THE INVENTION

An object of the invention is to develop a radial bearing unit of simple production and mounting on the bearing journal.

The object is achieved by a wheel bearing unit, in particular for commercial vehicles, having a wheel hub which is mounted rotatably on a bearing journal by means of two tapered roller bearings which are spaced apart from one another axially with in each case one outer ring, one inner ring and one roller crown ring which is arranged between the former and is formed from tapered rollers and a bearing cage for them, the tapered roller bearings being received by means of their outer rings on in each case one axial stop of the wheel hub such that they are directed counter to one another, the inner rings of the tapered roller bearings being spaced apart axially from one another by means of a sleeve, the wheel hub, tapered roller bearings and sleeve forming a self-retaining assembly in the non-installed state of the wheel bearing unit, and both tapered roller bearings being secured axially by means of in each case one securing means which is received directly on the wheel hub and covers the roller crown ring radially at least partially.

A simple self-retaining action of the tapered roller bearings and of the sleeve can be achieved during the time up to mounting of the assembly by way of two securing means which are arranged in each case on those sides of the tapered roller bearings which face away from one another. To this end, in particular, a play between the roller crown ring or the inner rings of the tapered roller bearings and the securing means is kept small, in order to limit the axial displacement thereof in the non-installed state. Contact or even a prestress of the securing means with respect to the roller crown ring or the inner ring is avoided at least in the installed state of the wheel bearing unit, in order to avoid frictional wear between components of the tapered roller bearing and the securing means which are loaded with a differential rotational speed. It can be provided here to clamp the securing means with respect to the roller crown ring or the inner ring in the non-installed state and to form a play between the securing means and the tapered roller bearing during mounting. To this end, for example, a securing means can be provided which is configured as a disk spring, is clamped axially between the axial stop and the inner ring or roller crown ring, and the prestress of which is canceled by means of a nut which is screwed onto the bearing journal in order to secure the wheel bearing unit, by it clamping between inner ring and nut and lifting up from the axial stop.

In one embodiment, at least one of the two securing means can be formed from a securing ring which is arranged in a radial groove of the wheel hub. Here, the securing ring can be stretched radially to the inside to such an extent that it engages radially over the roller crown ring and forms an axial stop for the inner ring. Here, the securing ring is provided with a small amount of play with respect to the inner ring, in order to avoid friction in the installed state.

As an alternative to a self-retaining action of the inner ring by way of the securing ring, the latter can form an axial stop for the roller crown ring, the inner ring being secured axially in the direction of the securing ring with respect to the roller crown ring by means of an annular rim. Here, the bearing cage of the roller crown ring is positionally secured axially, it also being possible here for a minimum play of the securing ring with respect to the bearing cage to be maintained.

In another embodiment, the securing ring is configured as a wave ring with a wave profile which is formed over the circumference. The wave ring can have an outer and inner profile formed in the circumferential direction, the outer profile engaging into the radial groove and the roller crown ring being secured axially by means of the inner profile thereof.

As an alternative or in addition, at least one of the tapered roller bearings can be fixed positionally by means of a securing ring which is of substantially U-shaped configuration with two limbs which are connected by means of a clip. Here, the free ends thereof of the limbs and corners between limb and clip engage radially into the radial groove, the roller crown ring being axially secured and positionally fixed by means of the limbs in the non-installed state of the wheel bearing unit. In order to increase the bearing area of the securing ring with respect to the roller crown ring, the bearing cage of the roller crown ring, a washer which is recessed in a substantially U-shaped manner can be arranged between the securing ring and the tapered roller bearing. By way of the cutout in the washer, the nut, as central nut, which is screwed onto the bearing journal for axial fixing of the wheel bearing unit can be clamped with the inner ring of the outer tapered roller bearing without removal of the washer.

As an alternative to a securing ring for the self-retaining action of the tapered roller bearings, on at least one side which faces a tapered roller bearing, the securing means can be formed from a seal which is arranged between the wheel hub and the inner ring and forms an axial stop for the roller crown ring, and the inner ring can be secured axially in the direction of the securing ring with respect to the roller crown ring by means of an annular rim.

BRIEF DESCRIPTION OF THE DRAWINGS

The nature and mode of operation of the present invention will now be more fully described in the following detailed description of the invention taken with the accompanying drawing figures, in which:

FIG. 1 is a partial section through a wheel bearing unit of the invention with two different securing means for each tapered roller bearing;

FIG. 2 is a tapered roller bearing in partial section with a securing ring which engages completely over the roller crown ring radially in accordance with FIG. 1;

FIG. 3 is a partial section of a tapered roller bearing with a securing ring which is modified with respect to FIG. 2 and engages over the roller crown ring partially;

FIG. 4 is a partial section through a tapered roller bearing with a securing means which is configured as a seal and is arranged between the wheel hub and inner ring;

FIG. 5 is a plan view of a tapered roller bearing with a securing means which is configured as a wave ring;

FIG. 6 is a plan view of a tapered roller bearing with a securing ring of U-shaped configuration;

FIG. 7 is a diagrammatic view of a washer for the securing ring of FIG. 6, and,

FIG. 8 is a partial section through a tapered roller bearing with a securing means which is configured as a spring element and is clamped axially between the wheel hub and the inner ring.

DETAILED DESCRIPTION OF THE INVENTION

At the outset, it should be appreciated that like drawing numbers on different drawing views identify identical, or functionally similar, structural elements of the invention. While the present invention is described with respect to what is presently considered to be the preferred aspects, it is to be understood that the invention as claimed is not limited to the disclosed aspects.

Furthermore, it is understood that this invention is not limited to the particular methodology, materials and modifications described and, as such, may, of course, vary. It is also understood that the terminology used herein is for the purpose of describing particular aspects only, and is not intended to limit the scope of the present invention, which is limited only by the appended claims.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this invention belongs. Although any methods, devices or materials similar or equivalent to those described herein can be used in the practice or testing of the invention, the preferred methods, devices, and materials are now described.

FIG. 1 shows the wheel bearing unit 100 in a diagrammatic illustration in partial section. The upper part of the wheel bearing unit 100 is arranged around the rotational axis 102 being shown. In the state in which it is removed from the bearing journal 103, the wheel bearing unit 100 forms the assembly 101 which is formed from the wheel hub 104 which receives a wheel, the two tapered roller bearings 105, 106 which are spaced apart axially and are spaced apart axially from one another on different diameters on said wheel hub 104, and the sleeve 107 which is arranged between said tapered roller bearings 105, 106.

The tapered roller bearings 105, 106 in each case have an outer ring 109, 110 which is received on the wheel hub 104, an inner ring 111, 112 which is provided for receiving the wheel bearing unit 100 on the bearing journal 103, and roller crown rings 113, 114 comprising the tapered rollers 117, 118 which are received in the bearing cage 115, 116 such that they are distributed over the circumference.

The rotational axes 102 a, 102 b of the tapered rollers 117, 118 are in each case inclined with respect to the rotational axis 102 so as to face one another, with the result that the wheel hub 104 is mounted radially and axially with respect to the bearing journal 103. The tapered roller bearings 105, 106 are placed on axial stops 121, 122 by means of the outer rings 109, 110 on their end sides 119, 120 which lie opposite one another.

In the installed state of the assembly 101, the end sides 123, 124, lying opposite one another, of the inner rings 111, 112 are clamped on one side by means of a central nut (not shown) which is screwed onto the end side of the bearing journal 103 and on the other side by means of the axial stop 125, the sleeve 107 spacing the inner rings 111, 112 apart.

In the removed state of the assembly 101, the inner rings 111, 112 are not prestressed axially against one another, with the result that they are not of captive configuration per se as a consequence of the inclined rotational axes 102 a, 102 b of the tapered rollers 117, 118. In order to produce the positional fixing of the inner rings 111, 112 and therefore of the roller crown rings 113, 114 in the removed state of the radial bearing unit 100 in the form of the assembly 101, in each case one axial securing means 108, 126 which in each case positionally fixes an inner ring 111, 112 axially is provided on the outer sides of the wheel bearing unit 100. The securing means 108, 126 are shown in detail individually in the following figures.

FIG. 2 shows a detail of the wheel bearing unit 100 of FIG. 1 with the tapered roller bearing 105. Here, the securing means 108 is configured as a securing ring 127 which is fitted into the radial groove 128 of the wheel hub 104 and engages radially over the roller crown ring 113 and loads the inner ring 111 axially. Here, a contact with the inner ring 111 can be produced, which contact limits the axial play of the inner ring 111 in such a way that the sleeve 107 remains centered between the inner rings 111 and 112 (FIG. 1). Here, friction of the securing ring 127 with respect to the inner ring 111 is kept low, in order, in the installed state, to avoid wear and frictional moments between the securing ring 127 which rotates with the wheel hub 104 and the fixed inner ring 111. As an alternative, a small axial gap can be provided between the securing ring 127 and the inner ring 111.

FIG. 3 shows a variant of the securing ring 127 which is shown in FIG. 2, in the form of the securing ring 227 of the radial bearing unit 200, which securing ring 227 is received in the radial groove 228 which is made in the wheel hub 204 at a small spacing from the outer ring 209. The securing ring 227 engages over the roller crown ring 213 partially radially and secures it against axial displacement. Here, an axial gap 229 is formed in order to prevent friction and wear between the roller crown ring 213 and the securing ring 227. As a consequence of the annular rims 230, 231 which are provided on the inner ring 211, the inner ring 211 is mounted substantially without axial play with respect to the tapered rollers 217, with the result that the inner ring is prevented by the annular rim 231 from being deflected axially in the case of an axially fixed roller crown ring 213. The axial fixing of the roller crown ring 213 by way of the securing ring 227 can be effected at the tapered rollers 217 or at the bearing cage (not shown).

FIG. 4 shows a detail of the wheel bearing unit 100 with the tapered roller bearing 106 which faces away from the free end of the bearing journal and the axial securing means 126 of which is configured as a seal 132. The seal 132 is introduced between the wheel hub 104 and the inner ring 112 and, by way of its friction, prevents an axial displacement of the inner ring with respect to the wheel hub 104, as a result of which it positionally fixes the inner ring 112 and also the roller crown ring 114 in the removed state of the wheel bearing unit 100.

FIG. 5 shows the wheel bearing unit 300 with the wheel hub 304 and the tapered roller bearing 305 with the inner ring 311 and the roller crown ring 313, which tapered roller bearing 305 is received by means of the outer ring 309 on the wheel hub 304. The axial positional securing of the inner ring 311 and of the roller crown ring 313 is effected by means of the securing ring 327 which is provided in this embodiment as a wave ring 333 with a wave profile which is configured in the form of radially inwardly and outwardly displaced waves 334, 335. Here, the waves 335 engage in each case into a radial groove 328 which is provided so as to be circumferential, whereas the radially inwardly directed waves 334 axially position the roller crown ring 313 and therefore, the inner ring 311 axially, since the inner ring 311, in accordance with the inner ring 211 of FIG. 3, has an annular rim (not shown) which corresponds to the annular rim 230.

FIG. 6 shows a further alternative of the wheel bearing unit 400 with the securing ring 427 which is configured to be open on one side and U-shaped. Here, the two limbs 436, 437 are connected by means of the clip 438, the free ends 439, 440 which are rolled up here and the corners 441, 442 being latched into the radial groove 428 of the wheel hub 404. The middle regions of the limbs 436, 437 sweep over the inner ring 411 and form the positional securing for the latter.

With reference to FIG. 6, FIG. 7 diagrammatically shows the washer 443 with the cutout 444, as a result of which the contour of said washer 443 is adapted to the securing ring 427. The washer 443 can be arranged between the securing ring 427 and the inner ring 411 and, as a consequence of the cutout 444, permits access of the central nut for loading the inner ring 411 during the mounting of the radial bearing unit on the bearing journal.

FIG. 8 shows a partial section of the wheel bearing unit 500 with the tapered roller bearing 505. In the embodiment shown, the securing means 508 is configured as a spring element 545, for example, as a disk spring, which is clamped axially between the inner ring 511 and the axial stop 546 of the wheel hub 504, with the result that, in the non-installed state of the wheel bearing unit 500, the inner ring 511 is positionally fixed and is clamped axially with respect to the sleeve 507, with the result that, in the non-installed state, the sleeve 507 remains centered between the two inner rings. During mounting of the wheel bearing unit 500 on the bearing journal 503, the central nut 547 is screwed onto the bearing journal and therefore, as the dashed illustration of the spring element 545′ shows, the spring element 545 is lifted up from the axial stop 546, with the result that, in the installed state of the wheel bearing unit 500, the prestress of the spring element 545 with respect to the inner ring 511 and its contact with the latter are canceled. An additional washer 548 can be provided between the central nut 547 and the spring element.

Thus, it is seen that the objects of the present invention are efficiently obtained, although modifications and changes to the invention should be readily apparent to those having ordinary skill in the art, which modifications are intended to be within the spirit and scope of the invention as claimed. It also is understood that the foregoing description is illustrative of the present invention and should not be considered as limiting. Therefore, other embodiments of the present invention are possible without departing from the spirit and scope of the present invention.

LIST OF REFERENCE NUMBERS

-   100 Wheel bearing unit -   101 Assembly -   102 Rotational axis -   102 a Rotational axis -   102 b Rotational axis -   103 Bearing journal -   104 Wheel hub -   105 Tapered roller bearing -   106 Tapered roller bearing -   107 Sleeve -   108 Securing means -   109 Outer ring -   110 Outer ring -   111 Inner ring -   112 Inner ring -   113 Roller crown ring -   114 Roller crown ring -   115 Bearing cage -   116 Bearing cage -   117 Tapered roller -   118 Tapered roller -   119 End side -   120 End side -   121 Axial stop -   122 Axial stop -   123 End side -   124 End side -   125 Axial stop -   126 Securing means -   127 Securing ring -   128 Radial groove -   132 Seal -   200 Wheel bearing unit -   204 Wheel hub -   209 Outer ring -   211 Inner ring -   213 Roller crown ring -   217 Tapered roller -   227 Securing ring -   228 Radial groove -   229 Axial gap -   230 Annular rim -   231 Annular rim -   300 Wheel bearing unit -   304 Wheel hub -   305 Tapered roller bearing -   309 Outer ring -   311 Inner ring -   313 Roller crown ring -   327 Securing ring -   328 Radial groove -   333 Wave ring -   334 Wave -   335 Wave -   400 Wheel bearing unit -   404 Wheel hub -   411 Inner ring -   427 Securing ring -   428 Radial groove -   436 Limb -   437 Limb -   438 Clip -   439 Free end -   440 Free end -   441 Corner -   442 Corner -   443 Washer -   444 Cutout -   500 Wheel bearing unit -   503 Bearing journal -   504 Wheel hub -   505 Tapered roller bearing -   507 Sleeve -   508 Securing means -   511 Inner ring -   545 Spring element -   545′ Spring element -   546 Axial stop -   547 Central nut -   548 Washer 

What is claimed is: 1-9. (canceled)
 10. A wheel bearing unit (100, 200, 300, 400, 500) for commercial vehicles, comprising: a bearing journal (103, 503); and, a wheel hub (104, 204, 304, 404, 504) mounted rotatably on said bearing journal (103, 503) by means of two tapered roller bearings (105, 106, 505) which are spaced apart from one another axially with an outer ring (109, 110, 209, 309), an inner ring (111, 112, 211, 311, 411, 511) and a roller crown ring (113, 114, 213, 313) which is arranged between the former and is formed from tapered rollers (117, 118, 217) and a bearing cage (115, 116) for them, wherein the tapered roller bearings (105, 106, 505) are received by means of outer rings (109, 209, 309) on an axial stop (121, 122) of the wheel hub (104, 204, 304, 404, 504) such that they are directed counter to one another, and inner rings (111, 112, 211, 311, 411, 511) of the tapered roller bearings (105, 106, 505) are spaced apart axially from one another by means of a sleeve (107, 507), and wherein the wheel hub (104, 204, 304, 404, 504), tapered roller bearing (105, 106, 505) and sleeve (107, 507) form a self-retaining assembly (101) in the non-installed state of the wheel bearing unit (100, 200, 300, 400, 500), both tapered roller bearings (105, 106, 505) being secured axially by means of one securing means (108, 508) which is received directly on the wheel hub (104, 204, 304, 404, 504) and covers the roller crown ring (113, 114, 213, 313) radially at least partially.
 11. The wheel bearing unit (100, 200, 300, 400) as recited in claim 10, wherein at least one of the two securing means (108) is formed from a securing ring (127, 227, 327, 427) which is arranged in a radial groove (128, 228, 328, 428) of the wheel hub (104, 204, 305, 404).
 12. The wheel bearing unit (100, 400) as recited in claim 11, wherein the securing ring (127, 427) forms an axial stop for the inner ring (111, 411).
 13. The wheel bearing unit (200, 300) as recited in claim 11, wherein the securing ring (227, 327) forms an axial stop for the roller crown ring (213, 313) and the inner ring (211, 311) and is secured axially in the direction of the securing ring (227, 327) with respect to the roller crown ring (213, 313) by means of an annular rim (230).
 14. The wheel bearing unit (300) as recited in claim 13, wherein the securing ring (327) is a wave ring (333) with a wave profile which is formed over a circumference and a radially outer wave (335) of which engages into the radial groove (328), and the roller crown ring (313) is secured axially by means of radially inner waves (334).
 15. The wheel bearing unit (400) as recited in claim 11, wherein the securing ring (427) is of substantially U-shaped configuration with two limbs (436, 437) which are connected by means of a clip (438), free ends (439, 440) of the limbs (436, 437) and corners (441, 442) between limbs (436, 437) and clip (438) being received in the radial groove (428), and the roller crown ring or the inner ring (411) being secured axially by means of the limbs (436, 437).
 16. The wheel bearing unit (400) as recited in claim 11, wherein a washer (443) which is recessed in a substantially U-shaped manner is arranged between the securing ring (427) and the tapered roller bearing.
 17. The wheel bearing unit (500) as recited in claim 10, wherein at least one securing means (508) is configured as a spring element (545) which is prestressed axially between the wheel hub (504) and the roller crown ring or inner ring (511) and the prestress of which is canceled during the mounting of the wheel bearing unit (500) on the bearing journal (503).
 18. The wheel bearing unit (100) as recited in claim 10, wherein at least one of the two securing means (126) is formed from a seal (132) which is arranged between the wheel hub (104) and the inner ring (112) and forms an axial stop for the roller crown ring (114). 